1. [Field of the Invention]
The present invention relates to data processing methods and apparatus, exposing methods and apparatus, recording media that stores programs for implementing the above methods and apparatus by function of software, and reticle masks made according to the above data processing methods, particularly to apparatus and methods for making reticle mask data (exposure data, check data, and verification data) from design data for manufacturing LSIs such as semiconductor devices, magnetic devices, liquid crystal devices, or printed circuit boards, and methods of performing exposure according to the reticle mask data.
2. [Description of the Related Art]
In a manufacturing process of LSIs such as semiconductor devices, design data that symbolically represents the circuit layouts on each semiconductor device to be manufactured, is first prepared by CAD (Computer-Aided Design) or the like. Data of a reticle, a photomask, or the like, (reticle mask data) representing a layout pattern used as an original for processing wafers, is then made on the basis of the design data. A photosensitive material is exposed according to the reticle mask data to make a reticle mask. The reticle mask is used for printing on wafers.
FIG. 1 is a block diagram showing a conventional data processing apparatus for making reticle mask data from design data. Referring to FIG. 1, the data processing apparatus 200 performs data processing to CAD data 1, which symbolically represents circuit layouts, to make reticle mask data 2. In accordance with the obtained reticle mask data 2, an exposing apparatus (not shown) performs exposure to make a reticle mask 3.
At first in the data processing apparatus 200, an apparatus grid data calculation section 6 calculates grid data on the basis of reticle accuracy data 4 and processing parameters 5 being input. The grid data is used for determining the basic size of the layout pattern of the reticle mask data 2 when the reticle mask data 2 is made from a circuit layout in the CAD data 1.
The grid data is made in the permissible minimum actual size in accordance with the minimum grid when the CAD data 1 is made, accuracy in pattern size on the reticle mask 3, etc. More specifically, the grid data is made such that every edge of the pattern data of any circuit element constituting the reticle mask data 2, is at a lattice point of the matrix defined according to the basic size set by the grid data.
The above-mentioned reticle accuracy data 4 gives information on permissible range of error in printing on wafers with the reticle mask 3 being made. The above-mentioned processing parameters 5 include various data such as layer composition data, sizing data, and scale data, which will be described below.
The layer composition data gives information on layer groups in case of dividing circuit patterns to make up the aimed semiconductor device, into layers in accordance with the roles and features of the circuit patterns, processing technique, conditions, etc. That is, the layer composition data gives information as to which layer each circuit pattern belongs to.
The sizing data gives information on size of each circuit pattern contained in the CAD data 1. The scale data gives information on scale of enlargement of the whole semiconductor chip represented by the CAD data 1. More specifically, the reticle mask data 2 is made by enlarging the CAD data 1 in accordance with the scale given by this scale data. Printing with the reticle mask 3 made according to the reticle mask data 2, is performed with reduction to the same scale as that of the original CAD data 1.
Next, an internal format conversion section 7 converts necessary one or ones of the CAD data 1, the reticle accuracy data 4, the processing parameters 5, and the grid data calculated by the apparatus grid data calculation section 6, into data 8 in accordance with the internal format of the data processing apparatus 200. A logical operation processing section 9 then performs logical operation to the converted internal format data 8 to perform processing of layer composition, sizing, enlargement, or the like, given by the processing parameters 5. Operated internal format data 10 is thereby made.
A format conversion/output section 11 then converts, in format, the operated internal format data 10 thus obtained, into data for exposing, and outputs it. The reticle mask data 2 is thereby made. The reticle mask data 2 thus obtained is circuit pattern data miniaturized according to the basic size of the grid data. Processing technique of, e.g., printing, varies in accordance with difference in the basic size of the pattern data.
The reticle mask data 2 made in the above data processing apparatus 200, includes check data and verification data in addition to the exposure data as described above. The check data is layout data for checking whether the circuit pattern formed on a substrate on the basis of the exposure data, has its correct pattern. This check data is made in the same process as the exposure data. The verification data is layout data for verifying on data whether the obtained reticle mask data 2 has its correct pattern, in a stage prior to printing on the substrate. This verification data is also made in the same process as the exposure data.
Recent development of LSI is being larger-scale with advance in CAD tool, and the term for development is requested to be short. With this, it is requested to put quickly a large number of high-quality LSIs on the market. For this purpose, there has arisen the necessity of making each reticle mask with high accuracy used as a base in manufacturing semiconductor chips, in a short time, and of shortening the time for making reticle check data and verification data.
In a conventional technique of making reticle mask data, however, grid data is made in the permissible minimum actual size according to a mask design rule. So, even when each semiconductor chip being manufactured, includes a circuit pattern requiring not so high accuracy in grid, grid data is made with equally minute accuracy (small basic size).
As a result, processing time for making reticle mask data using the grid data, becomes long, besides, processing time for actually performing exposure, printing, comparative check, or data verification, on the basis of the obtained reticle mask data, also becomes long. These are problems.
Besides, particularly in a development process of a semiconductor device, design change in circuit or condition may be done, e.g., for improving the performance of the device. Such change brings change in layout pattern of, e.g., a reticle or a photomask.
FIG. 2 is a flowchart showing an outline of a process for making a reticle (reticle mask) on the basis of design data. FIG. 2 shows the process of making a first reticle and the process of making a revised reticle.
At first, first design data 101 representing the layout pattern of a reticle is made with CAD. Data processing 111 is performed to the first design data 101 to make exposure data 102. Data processing 111 includes conversion of the first design data 101 into internal format data, figure logical operation, sizing, etc. The exposure data 102 thus obtained is output to a recording medium (not shown) and stored therein.
The obtained exposure data 102 is then supplied to an exposing apparatus, wherein exposure 112 of a resist and then etching are performed. A reticle 103 is thereby made. Printing 113 on a glass substrate is then performed with the reticle 103. A wafer 104 is thereby made. The wafer 104 thus obtained is subjected to a test 114 for, e.g., judging whether the circuit pattern formed on the substrate has its correct pattern, or examining the performance of the circuit pattern. When the conditions are satisfactory, the reticle completion 106 is confirmed.
If there is the necessity of, e.g., improving the performance, revise 115 of the design data of the reticle pattern is made with CAD to make revised design data 105. Data processing 116 is performed to the revised design data 105 in the same manner as data processing 111 as described above, to make revised exposure data 107. The revised exposure data 107 thus obtained is also output to the recording medium (not shown) and stored therein separately from the first exposure data 102.
Using the revised exposure data 107 thus obtained, exposure 112 is again performed in the exposing apparatus to make a reticle 103. Printing 113 is then performed to make a wafer 104. The wafer 104 thus newly obtained is subjected to a test 114. When the conditions are satisfactory, the reticle completion 106 is confirmed. If there is the necessity of further improvement, processing as described above is repeated.
With rapid engineering development, recent LSI development requests to make such design data and exposure data in a short time. However, the data quantity of such design data and exposure data is apt to increase with increase in density of circuit patterns. This increases processing load. For making such design data and exposure data in a short time, it is required to reduce the data quantity being processed, and steps of the making process.
In the conventional technique, however, when the revised exposure data is made from the revised design data, data processing is redundantly performed also to portions that have not changed from the respectively corresponding portions of the first design data. For this reason, the data quantity being processed and the number of steps are substantially the same as those in case of making the first exposure data. This will be described below with reference to drawings.
FIG. 3 is a representation for illustrating the operation of making first exposure data from first design data. Referring to FIG. 3, blocks a to f shown by broken lines in first design data 101, represent groups of cells in a semiconductor device, respectively. Each group forms a module. In each of the modules a to f, its peculiar circuit layout is symbolically drawn by CAD.
First exposure data 102 is made by performing data processing 111 on the basis of the first design data 101. Blocks A to F shown by broken lines in the first exposure data 102 represent modules of the exposure data made from the respective modules a to f in the first design data 101. In each of the modules A to F, pattern data is drawn which represents portions to be irradiated with electron beams in an exposing apparatus, and portions not to be irradiated.
Here, let it be supposed that the data quantity of the first design data 101 is xe2x80x9c100xe2x80x9d (which means that the data quantity being processed in the data processing apparatus is 100% the whole first design data 101). In this case, in data processing 111, the data quantity being processed in making the first exposure data 102 is xe2x80x9c100xe2x80x9d because data processing is performed to all the modules a to f in the first design data 101.
FIG. 4 is a representation for illustrating the operation of making revised exposure data from revised design data. Referring to FIG. 4, in revised design data 105, the module f in the first design data 101 shown in FIG. 3 has been revised to be a new module g. The other modules a to e have not been revised, so they are the same as those of the first design data 101.
Revised exposure data 107 is made by performing data processing 116 on the basis of the revised design data 105. The block G shown by a dot-dash line in the revised exposure data 107 represents a module of the exposure data made from the module g in the revised design data 105. The other blocks A to E represent modules of the exposure data made from the respective modules a to e in the revised design data 105.
When data processing 116 is performed to the revised design data 105, all the modules including the revised module g are input to the data processing apparatus. So, the data quantity of the revised design data 105 is xe2x80x9c100xe2x80x9d. Because data processing is performed to all the modules a to e and g in the revised design data 105, it requires the same number of steps as that in case of processing the first design data 101. Besides, the data quantity being processed is xe2x80x9c100xe2x80x9d.
Conventionally, data processing for revised data is redundantly performed also to the portions (modules a to e) which have not been revised, as described above. Consequently, there is a redundancy in data processing, and so the time for making the exposure data is long. Besides, since the revised design data 105 contains also the portions with no revise, the data quantity of the revised exposure data 107 made from the revised design data 105 becomes large. Consequently, the data quantity being stored in a recording medium also becomes large. Besides, in case of transferring the obtained exposure data to a factory where exposure is performed, the time for transferring becomes long because the data quantity of either of the first and revised exposure data is large. These are problems.
It is the first object of the present invention to shorten the making time of reticle mask data and the processing time of each process of exposure, printing, comparative check, and data verification on the basis of an obtained reticle mask.
It is the second object of the present invention to reduce the data quantity of revised exposure data and steps of making it in order to make the exposure data in a short time, store the exposure data with a small data quantity, and shorten the transference time of the exposure data.
According to the present invention, the minimum grid and the present area of a circuit element are obtained for each layer of circuit patterns given by design data, and an overlap area of present areas is obtained, and, on the basis of the result, it is determined whether the layers including the overlap area should be processed according to a single common grid or different grids, and a grid is obtained for each layer.
According to this feature of the present invention, each layer can be assigned the grid with the minimum accuracy required for the layer. As for a portion requiring a grid with not so minute accuracy, a grid with more minute accuracy than it requires may not be used. That is, a portion requiring no minute accuracy can be assigned a grid with relatively rough accuracy. This makes it possible to reduce considerably operation load in making reticle mask data (exposure data, check data, and verification data), and processing load in actually performing exposure, printing, comparative check, or data verification. As a result, the time for manufacturing LSI such as a semiconductor device can be considerably shortened. Besides, the rate of observance of the time limit of delivery can be improved.
According to another aspect of the present invention, the position of a revised portion is designated on revised design data when revised exposure data is made from the revised design data, data processing is performed only to the designated revised portion, and position data of the revised portion is added into a header or footer portion of the obtained revised exposure data.
According to this feature of the present invention, when revised exposure data is made from revised design data, data processing may not be performed to the duplicate portion of that of the design data before revision, and may be performed only to the revised portion designated on the revised design data. This makes it possible to reduce the number of processing steps and shorten the time for making the exposure data, besides, to reduce the data quantity of the revised exposure data. Because of the data quantity thus reduced, the data can be stored in a small data quantity, and transferred in a short transference time.